Has anyone tried out the new Cayenne GTS and, if so, how does it compare to the X5M or X5 5.0si?

Performance-wise, the real competitor of the X5M is a Cayenne Turbo. Cayenne GTS would probably compete with an X5 50i with an M Sport package (and X5 50i would still be .1 sec faster to 60Mph).

Some people who had driven both cars said that Cayenne Turbo drives "smaller" than the X5M (makes sense since X5M is 584 Lbs heavier). However, price-wise there is a HUGE gap. Base prices are $108,750 for Cayenne Turbo and $88,850 for the X5M. A well-loaded Cayenne Turbo will run you $130K, while a well-loaded X5M will only be about $95K. Incidentally, that's how much Porsche is going to charge you for a well-loaded Cayenne GTS. Another problem is financing/leasing rates. Porsche's finance/lease rates are obnoxious and residuals are brutal. Porsche never has ANY promotions or special offers, BMW has something almost every month, especially around holidays. When I was shopping for my car in late 2011, X5M leases were $1200-$1400/mo, while Cayenne Turbo started at around $1,900. Guess which one I went with?